Just had a quick look. I notice MAV uses <> at the end of a paragraph in addition to leaving the blank line to wichh MC adds a P break but in upper case. It doesn't show no any of mine but perhaps that could cause the effects on certain browsers.
What is interesting is such things tend to be posting quirks of one person. If you get 2 people doing the same in one thread - there is a chance that what you are really reading is the same person chatting to themselves.
Jon